org.apache.commons.geometry.io.euclidean.threed.obj

Class PolygonObjParser.Face

java.lang.Object

org.apache.commons.geometry.io.euclidean.threed.obj.PolygonObjParser.Face

Enclosing class:

PolygonObjParser

public static final class PolygonObjParser.Face
extends Object

Class representing an OBJ face definition. Faces are defined with the format

f v1/vt1/vn1 v2/vt2/vn2 v3/vt3/vn3 ...

where the v elements are indices into the model vertices, the vt elements are indices into the model texture coordinates, and the vn elements are indices into the model normal coordinates. Only the vertex indices are required.

All vertex attribute indices are normalized to be 0-based and positive and all faces are assumed to define geometrically valid convex polygons.

Method Summary

Modifier and Type	Method and Description
Vector3D	computeNormalFromVertices(IntFunction<Vector3D> modelVertexFn) Compute a normal for the face using its first three vertices.
Vector3D	getDefinedCompositeNormal(IntFunction<Vector3D> modelNormalFn) Get a composite normal for the face by computing the sum of all defined vertex normals and normalizing the result.
int[]	getNormalIndices() Get the normal indices for the face.
int[]	getTextureIndices() Get the texture indices for the face.
List<PolygonObjParser.VertexAttributes>	getVertexAttributes() Get the list of vertex attributes for the instance.
List<PolygonObjParser.VertexAttributes>	getVertexAttributesCounterClockwise(Vector3D normal, IntFunction<Vector3D> modelVertexFn) Get the vertex attributes for the face listed in the order that produces a counter-clockwise winding of vertices when viewed looking down the given normal direction.
int[]	getVertexIndices() Get the vertex indices for the face.
List<Vector3D>	getVertices(IntFunction<Vector3D> modelVertexFn) Get the face vertices in the order defined in the face definition.
List<Vector3D>	getVerticesCounterClockwise(Vector3D normal, IntFunction<Vector3D> modelVertexFn) Get the face vertices in the order that produces a counter-clockwise winding when viewed looking down the given normal.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getVertexAttributes

public List<PolygonObjParser.VertexAttributes> getVertexAttributes()

Get the list of vertex attributes for the instance.

Returns:

list of vertex attribute

getDefinedCompositeNormal

public Vector3D getDefinedCompositeNormal(IntFunction<Vector3D> modelNormalFn)

Get a composite normal for the face by computing the sum of all defined vertex normals and normalizing the result. Null is returned if no vertex normals are defined or the defined normals sum to zero.

Parameters:

modelNormalFn - function used to access normals parsed earlier in the model; callers are responsible for storing these values as they are parsed

Returns:

composite face normal or null if no composite normal can be determined from the normals defined for the face

computeNormalFromVertices

public Vector3D computeNormalFromVertices(IntFunction<Vector3D> modelVertexFn)

Compute a normal for the face using its first three vertices. The vertices will wind in a counter-clockwise direction when viewed looking down the returned normal. Null is returned if the normal could not be determined, which would be the case if the vertices lie in the same line or two or more are equal.

Parameters:

modelVertexFn - function used to access model vertices parsed earlier in the content; callers are responsible for storing these values as they are passed

Returns:

a face normal computed from the first 3 vertices or null if a normal cannot be determined

getVertexAttributesCounterClockwise

public List<PolygonObjParser.VertexAttributes> getVertexAttributesCounterClockwise(Vector3D normal,
                                                                                   IntFunction<Vector3D> modelVertexFn)

Get the vertex attributes for the face listed in the order that produces a counter-clockwise winding of vertices when viewed looking down the given normal direction. If normal is null, the original vertex sequence is used.

Parameters:

normal - requested face normal; may be null

modelVertexFn - function used to access model vertices parsed earlier in the content; callers are responsible for storing these values as they are passed

Returns:

list of vertex attributes for the face, oriented to correspond with the given face normal

getVertices

public List<Vector3D> getVertices(IntFunction<Vector3D> modelVertexFn)

Get the face vertices in the order defined in the face definition.

Parameters:

modelVertexFn - function used to access model vertices parsed earlier in the content; callers are responsible for storing these values as they are passed

Returns:

face vertices in their defined ordering

getVerticesCounterClockwise

public List<Vector3D> getVerticesCounterClockwise(Vector3D normal,
                                                  IntFunction<Vector3D> modelVertexFn)

Get the face vertices in the order that produces a counter-clockwise winding when viewed looking down the given normal.

Parameters:

normal - requested face normal

modelVertexFn - function used to access model vertices parsed earlier in the content; callers are responsible for storing these values as they are passed

Returns:

face vertices in the order that produces a counter-clockwise winding when viewed looking down the given normal

See Also:

getVertexAttributesCounterClockwise(Vector3D, IntFunction)

getVertexIndices

public int[] getVertexIndices()

Get the vertex indices for the face.

Returns:

vertex indices for the face

getTextureIndices

public int[] getTextureIndices()

Get the texture indices for the face. The value -1 is used if a texture index is not set.

Returns:

texture indices

getNormalIndices

public int[] getNormalIndices()

Get the normal indices for the face. The value -1 is used if a texture index is not set.

Returns:

normal indices